1. Field of the Invention
This invention relates generally to a battery charger, and more particularly to a self-contained emergency battery charger for motors having a starter battery and an alternator or generator.
2. Description of the Prior Art
A motor vehicle storage battery frequently falls into a state of discharge such that it cannot deliver sufficient current to the starter motor. This occurs most commonly due to excessive current drain, insufficient charging time and severe environmental conditions.
To start a vehicle whose storage battery has run down requires either bypassing the electrical starting system entirely, or supplying the system with an additional source of electrical power. The former is generally accomplished by push-starting the vehicle; the latter by using jumper cables. Push starting requires assistance in the form of a push vehicle or muscle power. Additionally, only cars fitted with standard transmissions can be push started. Jump starting also requires the aid of an additional vehicle. Further, cables must be available and must be externally connected, requiring the user to exit the vehicle, and be exposed to the hazards of a possible battery explosion and associated mishaps as a result of misconnection.
Several self-contained means for charging a vehicle's inoperative battery to enable the vehicle to start have been developed. U.S. Pat. No. 4,004,208 issued to Tamminen discloses a starting aid which may be contained within a vehicle to provide an emergency power source. This starting aid is not itself readily rechargeable and requires approximately fifteen hours to recharge with the vehicle's engine running. This is because the additional voltage supplied by the vehicle's alternator or generator is required to recharge the charging aid batteries. Because of this very slight voltage differential, no fast charge mode is possible in the invention of Tamminen.
Other devices are known in the art including those disclosed in U.S. Pat. No. 3,504,262 issued to Sada et al, U.S. Pat. No. 4,258,305 issued to Anglin and U.S. Pat. No. 3,763,415 issued to Ownby. These all require either a connection to an external power source, or are insuffiently portable or require extensive charging and/or recharging time.